mox/imapserver/parse.go
Mechiel Lukkien 5b20cba50a
switch to slog.Logger for logging, for easier reuse of packages by external software
we don't want external software to include internal details like mlog.
slog.Logger is/will be the standard.

we still have mlog for its helper functions, and its handler that logs in
concise logfmt used by mox.

packages that are not meant for reuse still pass around mlog.Log for
convenience.

we use golang.org/x/exp/slog because we also support the previous Go toolchain
version. with the next Go release, we'll switch to the builtin slog.
2023-12-14 13:45:52 +01:00

945 lines
20 KiB
Go

package imapserver
import (
"errors"
"fmt"
"net/textproto"
"strconv"
"strings"
"time"
"golang.org/x/exp/slog"
)
var (
listWildcards = "%*"
char = charRange('\x01', '\x7f')
ctl = charRange('\x01', '\x19')
quotedSpecials = `"\`
respSpecials = "]"
atomChar = charRemove(char, "(){ "+ctl+listWildcards+quotedSpecials+respSpecials)
astringChar = atomChar + respSpecials
)
func charRange(first, last rune) string {
r := ""
c := first
r += string(c)
for c < last {
c++
r += string(c)
}
return r
}
func charRemove(s, remove string) string {
r := ""
next:
for _, c := range s {
for _, x := range remove {
if c == x {
continue next
}
}
r += string(c)
}
return r
}
type parser struct {
// Orig is the line in original casing, and upper in upper casing. We often match
// against upper for easy case insensitive handling as IMAP requires, but sometimes
// return from orig to keep the original case.
orig string
upper string
o int // Current offset in parsing.
contexts []string // What we're parsing, for error messages.
conn *conn
}
// toUpper upper cases bytes that are a-z. strings.ToUpper does too much. and
// would replace invalid bytes with unicode replacement characters, which would
// break our requirement that offsets into the original and upper case strings
// point to the same character.
func toUpper(s string) string {
r := []byte(s)
for i, c := range r {
if c >= 'a' && c <= 'z' {
r[i] = c - 0x20
}
}
return string(r)
}
func newParser(s string, conn *conn) *parser {
return &parser{s, toUpper(s), 0, nil, conn}
}
func (p *parser) xerrorf(format string, args ...any) {
var err error
errmsg := fmt.Sprintf(format, args...)
remaining := fmt.Sprintf("remaining %q", p.orig[p.o:])
if len(p.contexts) > 0 {
remaining += ", context " + strings.Join(p.contexts, ",")
}
remaining = " (" + remaining + ")"
if p.conn.account != nil {
errmsg += remaining
err = errors.New(errmsg)
} else {
err = errors.New(errmsg + remaining)
}
panic(syntaxError{"", "", errmsg, err})
}
func (p *parser) context(s string) func() {
p.contexts = append(p.contexts, s)
return func() {
p.contexts = p.contexts[:len(p.contexts)-1]
}
}
func (p *parser) empty() bool {
return p.o == len(p.upper)
}
func (p *parser) xempty() {
if !p.empty() {
p.xerrorf("leftover data")
}
}
func (p *parser) hasPrefix(s string) bool {
return strings.HasPrefix(p.upper[p.o:], s)
}
func (p *parser) take(s string) bool {
if !p.hasPrefix(s) {
return false
}
p.o += len(s)
return true
}
func (p *parser) xtake(s string) {
if !p.take(s) {
p.xerrorf("expected %s", s)
}
}
func (p *parser) xnonempty() {
if p.empty() {
p.xerrorf("unexpected end")
}
}
func (p *parser) xtakeall() string {
r := p.orig[p.o:]
p.o = len(p.orig)
return r
}
func (p *parser) xtake1n(n int, what string) string {
if n == 0 {
p.xerrorf("expected chars from %s", what)
}
return p.xtaken(n)
}
func (p *parser) xtakechars(s string, what string) string {
p.xnonempty()
for i, c := range p.orig[p.o:] {
if !contains(s, c) {
return p.xtake1n(i, what)
}
}
return p.xtakeall()
}
func (p *parser) xtaken(n int) string {
if p.o+n > len(p.orig) {
p.xerrorf("not enough data")
}
r := p.orig[p.o : p.o+n]
p.o += n
return r
}
func (p *parser) space() bool {
return p.take(" ")
}
func (p *parser) xspace() {
if !p.space() {
p.xerrorf("expected space")
}
}
func (p *parser) digits() string {
var n int
for _, c := range p.upper[p.o:] {
if c < '0' || c > '9' {
break
}
n++
}
if n == 0 {
return ""
}
s := p.upper[p.o : p.o+n]
p.o += n
return s
}
func (p *parser) nznumber() (uint32, bool) {
o := p.o
for o < len(p.upper) && p.upper[o] >= '0' && p.upper[o] <= '9' {
o++
}
if o == p.o {
return 0, false
}
if n, err := strconv.ParseUint(p.upper[p.o:o], 10, 32); err != nil {
return 0, false
} else if n == 0 {
return 0, false
} else {
p.o = o
return uint32(n), true
}
}
func (p *parser) xnznumber() uint32 {
n, ok := p.nznumber()
if !ok {
p.xerrorf("expected non-zero number")
}
return n
}
func (p *parser) number() (uint32, bool) {
o := p.o
for o < len(p.upper) && p.upper[o] >= '0' && p.upper[o] <= '9' {
o++
}
if o == p.o {
return 0, false
}
n, err := strconv.ParseUint(p.upper[p.o:o], 10, 32)
if err != nil {
return 0, false
}
p.o = o
return uint32(n), true
}
func (p *parser) xnumber() uint32 {
n, ok := p.number()
if !ok {
p.xerrorf("expected number")
}
return n
}
func (p *parser) xnumber64() int64 {
s := p.digits()
if s == "" {
p.xerrorf("expected number64")
}
v, err := strconv.ParseInt(s, 10, 63) // ../rfc/9051:6794 ../rfc/7162:297
if err != nil {
p.xerrorf("parsing number64 %q: %v", s, err)
}
return v
}
func (p *parser) xnznumber64() int64 {
v := p.xnumber64()
if v == 0 {
p.xerrorf("expected non-zero number64")
}
return v
}
// l should be a list of uppercase words, the first match is returned
func (p *parser) takelist(l ...string) (string, bool) {
for _, w := range l {
if p.take(w) {
return w, true
}
}
return "", false
}
func (p *parser) xtakelist(l ...string) string {
w, ok := p.takelist(l...)
if !ok {
p.xerrorf("expected one of %s", strings.Join(l, ","))
}
return w
}
func (p *parser) xstring() (r string) {
if p.take(`"`) {
esc := false
r := ""
for i, c := range p.orig[p.o:] {
if c == '\\' {
esc = true
} else if c == '\x00' || c == '\r' || c == '\n' {
p.xerrorf("invalid nul, cr or lf in string")
} else if esc {
if c == '\\' || c == '"' {
r += string(c)
esc = false
} else {
p.xerrorf("invalid escape char %c", c)
}
} else if c == '"' {
p.o += i + 1
return r
} else {
r += string(c)
}
}
p.xerrorf("missing closing dquote in string")
}
size, sync := p.xliteralSize(100*1024, false)
s := p.conn.xreadliteral(size, sync)
line := p.conn.readline(false)
p.orig, p.upper, p.o = line, toUpper(line), 0
return s
}
func (p *parser) xnil() {
p.xtake("NIL")
}
// Returns NIL as empty string.
func (p *parser) xnilString() string {
if p.take("NIL") {
return ""
}
return p.xstring()
}
func (p *parser) xastring() string {
if p.hasPrefix(`"`) || p.hasPrefix("{") || p.hasPrefix("~{") {
return p.xstring()
}
return p.xtakechars(astringChar, "astring")
}
func contains(s string, c rune) bool {
for _, x := range s {
if x == c {
return true
}
}
return false
}
func (p *parser) xtag() string {
p.xnonempty()
for i, c := range p.orig[p.o:] {
if c == '+' || !contains(astringChar, c) {
return p.xtake1n(i, "tag")
}
}
return p.xtakeall()
}
func (p *parser) xcommand() string {
for i, c := range p.upper[p.o:] {
if !(c >= 'A' && c <= 'Z' || c == ' ' && p.upper[p.o:p.o+i] == "UID") {
return p.xtake1n(i, "command")
}
}
return p.xtakeall()
}
func (p *parser) remainder() string {
return p.orig[p.o:]
}
// ../rfc/9051:6565
func (p *parser) xflag() string {
w, _ := p.takelist(`\`, "$")
s := w + p.xatom()
if s[0] == '\\' {
switch strings.ToLower(s) {
case `\answered`, `\flagged`, `\deleted`, `\seen`, `\draft`:
default:
p.xerrorf("unknown system flag %s", s)
}
}
return s
}
func (p *parser) xflagList() (l []string) {
p.xtake("(")
if !p.hasPrefix(")") {
l = append(l, p.xflag())
}
for !p.take(")") {
p.xspace()
l = append(l, p.xflag())
}
return
}
func (p *parser) xatom() string {
return p.xtakechars(atomChar, "atom")
}
func (p *parser) xmailbox() string {
s := p.xastring()
// UTF-7 is deprecated in IMAP4rev2. IMAP4rev1 does not fully forbid
// UTF-8 returned in mailbox names. We'll do our best by attempting to
// decode utf-7. But if that doesn't work, we'll just use the original
// string.
// ../rfc/3501:964
if !p.conn.enabled[capIMAP4rev2] {
ns, err := utf7decode(s)
if err != nil {
p.conn.log.Infox("decoding utf7 or mailbox name", err, slog.String("name", s))
} else {
s = ns
}
}
return s
}
// ../rfc/9051:6605
func (p *parser) xlistMailbox() string {
if p.hasPrefix(`"`) || p.hasPrefix("{") {
return p.xstring()
}
return p.xtakechars(atomChar+listWildcards+respSpecials, "list-char")
}
// ../rfc/9051:6707 ../rfc/9051:6848 ../rfc/5258:1095 ../rfc/5258:1169 ../rfc/5258:1196
func (p *parser) xmboxOrPat() ([]string, bool) {
if !p.take("(") {
return []string{p.xlistMailbox()}, false
}
l := []string{p.xlistMailbox()}
for !p.take(")") {
p.xspace()
l = append(l, p.xlistMailbox())
}
return l, true
}
// ../rfc/9051:7056, RECENT ../rfc/3501:5047, APPENDLIMIT ../rfc/7889:252, HIGHESTMODSEQ ../rfc/7162:2452
func (p *parser) xstatusAtt() string {
w := p.xtakelist("MESSAGES", "UIDNEXT", "UIDVALIDITY", "UNSEEN", "DELETED", "SIZE", "RECENT", "APPENDLIMIT", "HIGHESTMODSEQ")
if w == "HIGHESTMODSEQ" {
// HIGHESTMODSEQ is a CONDSTORE-enabling parameter. ../rfc/7162:375
p.conn.enabled[capCondstore] = true
}
return w
}
// ../rfc/9051:7133 ../rfc/9051:7034
func (p *parser) xnumSet0(allowStar, allowSearch bool) (r numSet) {
defer p.context("numSet")()
if allowSearch && p.take("$") {
return numSet{searchResult: true}
}
r.ranges = append(r.ranges, p.xnumRange0(allowStar))
for p.take(",") {
r.ranges = append(r.ranges, p.xnumRange0(allowStar))
}
return r
}
func (p *parser) xnumSet() (r numSet) {
return p.xnumSet0(true, true)
}
// parse numRange, which can be just a setNumber.
func (p *parser) xnumRange0(allowStar bool) (r numRange) {
if allowStar && p.take("*") {
r.first.star = true
} else {
r.first.number = p.xnznumber()
}
if p.take(":") {
r.last = &setNumber{}
if allowStar && p.take("*") {
r.last.star = true
} else {
r.last.number = p.xnznumber()
}
}
return
}
// ../rfc/9051:6989 ../rfc/3501:4977
func (p *parser) xsectionMsgtext() (r *sectionMsgtext) {
defer p.context("sectionMsgtext")()
msgtextWords := []string{"HEADER.FIELDS.NOT", "HEADER.FIELDS", "HEADER", "TEXT"}
w := p.xtakelist(msgtextWords...)
r = &sectionMsgtext{s: w}
if strings.HasPrefix(w, "HEADER.FIELDS") {
p.xspace()
p.xtake("(")
r.headers = append(r.headers, textproto.CanonicalMIMEHeaderKey(p.xastring()))
for {
if p.take(")") {
break
}
p.xspace()
r.headers = append(r.headers, textproto.CanonicalMIMEHeaderKey(p.xastring()))
}
}
return
}
// ../rfc/9051:6999 ../rfc/3501:4991
func (p *parser) xsectionSpec() (r *sectionSpec) {
defer p.context("parseSectionSpec")()
n, ok := p.nznumber()
if !ok {
return &sectionSpec{msgtext: p.xsectionMsgtext()}
}
defer p.context("part...")()
pt := &sectionPart{}
pt.part = append(pt.part, n)
for {
if !p.take(".") {
break
}
if n, ok := p.nznumber(); ok {
pt.part = append(pt.part, n)
continue
}
if p.take("MIME") {
pt.text = &sectionText{mime: true}
break
}
pt.text = &sectionText{msgtext: p.xsectionMsgtext()}
break
}
return &sectionSpec{part: pt}
}
// ../rfc/9051:6985 ../rfc/3501:4975
func (p *parser) xsection() *sectionSpec {
defer p.context("parseSection")()
p.xtake("[")
if p.take("]") {
return &sectionSpec{}
}
r := p.xsectionSpec()
p.xtake("]")
return r
}
// ../rfc/9051:6841
func (p *parser) xpartial() *partial {
p.xtake("<")
offset := p.xnumber()
p.xtake(".")
count := p.xnznumber()
p.xtake(">")
return &partial{offset, count}
}
// ../rfc/9051:6987
func (p *parser) xsectionBinary() (r []uint32) {
p.xtake("[")
if p.take("]") {
return nil
}
r = append(r, p.xnznumber())
for {
if !p.take(".") {
break
}
r = append(r, p.xnznumber())
}
p.xtake("]")
return r
}
var fetchAttWords = []string{
"ENVELOPE", "FLAGS", "INTERNALDATE", "RFC822.SIZE", "BODYSTRUCTURE", "UID", "BODY.PEEK", "BODY", "BINARY.PEEK", "BINARY.SIZE", "BINARY",
"RFC822.HEADER", "RFC822.TEXT", "RFC822", // older IMAP
"MODSEQ", // CONDSTORE extension.
}
// ../rfc/9051:6557 ../rfc/3501:4751 ../rfc/7162:2483
func (p *parser) xfetchAtt(isUID bool) (r fetchAtt) {
defer p.context("fetchAtt")()
f := p.xtakelist(fetchAttWords...)
r.peek = strings.HasSuffix(f, ".PEEK")
r.field = strings.TrimSuffix(f, ".PEEK")
switch r.field {
case "BODY":
if p.hasPrefix("[") {
r.section = p.xsection()
if p.hasPrefix("<") {
r.partial = p.xpartial()
}
}
case "BINARY":
r.sectionBinary = p.xsectionBinary()
if p.hasPrefix("<") {
r.partial = p.xpartial()
}
case "BINARY.SIZE":
r.sectionBinary = p.xsectionBinary()
case "MODSEQ":
// The RFC text mentions MODSEQ is only for FETCH, not UID FETCH, but the ABNF adds
// the attribute to the shared syntax, so UID FETCH also implements it.
// ../rfc/7162:905
// The wording about when to respond with a MODSEQ attribute could be more clear. ../rfc/7162:923 ../rfc/7162:388
// MODSEQ attribute is a CONDSTORE-enabling parameter. ../rfc/7162:377
p.conn.xensureCondstore(nil)
}
return
}
// ../rfc/9051:6553 ../rfc/3501:4748
func (p *parser) xfetchAtts(isUID bool) []fetchAtt {
defer p.context("fetchAtts")()
fields := func(l ...string) []fetchAtt {
r := make([]fetchAtt, len(l))
for i, s := range l {
r[i] = fetchAtt{field: s}
}
return r
}
if w, ok := p.takelist("ALL", "FAST", "FULL"); ok {
switch w {
case "ALL":
return fields("FLAGS", "INTERNALDATE", "RFC822.SIZE", "ENVELOPE")
case "FAST":
return fields("FLAGS", "INTERNALDATE", "RFC822.SIZE")
case "FULL":
return fields("FLAGS", "INTERNALDATE", "RFC822.SIZE", "ENVELOPE", "BODY")
}
panic("missing case")
}
if !p.hasPrefix("(") {
return []fetchAtt{p.xfetchAtt(isUID)}
}
l := []fetchAtt{}
p.xtake("(")
for {
l = append(l, p.xfetchAtt(isUID))
if !p.take(" ") {
break
}
}
p.xtake(")")
return l
}
func xint(p *parser, s string) int {
v, err := strconv.ParseInt(s, 10, 32)
if err != nil {
p.xerrorf("bad int %q: %v", s, err)
}
return int(v)
}
func (p *parser) digit() (string, bool) {
if p.empty() {
return "", false
}
c := p.orig[p.o]
if c < '0' || c > '9' {
return "", false
}
s := p.orig[p.o : p.o+1]
p.o++
return s, true
}
func (p *parser) xdigit() string {
s, ok := p.digit()
if !ok {
p.xerrorf("expected digit")
}
return s
}
// ../rfc/9051:6492 ../rfc/3501:4695
func (p *parser) xdateDayFixed() int {
if p.take(" ") {
return xint(p, p.xdigit())
}
return xint(p, p.xdigit()+p.xdigit())
}
var months = []string{"jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct", "nov", "dec"}
// ../rfc/9051:6495 ../rfc/3501:4698
func (p *parser) xdateMonth() time.Month {
s := strings.ToLower(p.xtaken(3))
for i, m := range months {
if m == s {
return time.Month(1 + i)
}
}
p.xerrorf("unknown month %q", s)
return 0
}
// ../rfc/9051:7120 ../rfc/3501:5067
func (p *parser) xtime() (int, int, int) {
h := xint(p, p.xtaken(2))
p.xtake(":")
m := xint(p, p.xtaken(2))
p.xtake(":")
s := xint(p, p.xtaken(2))
return h, m, s
}
// ../rfc/9051:7159 ../rfc/3501:5083
func (p *parser) xzone() (string, int) {
sign := p.xtakelist("+", "-")
s := p.xtaken(4)
v := xint(p, s)
seconds := (v/100)*3600 + (v%100)*60
if sign[0] == '-' {
seconds = -seconds
}
return sign + s, seconds
}
// ../rfc/9051:6502 ../rfc/3501:4713
func (p *parser) xdateTime() time.Time {
// DQUOTE date-day-fixed "-" date-month "-" date-year SP time SP zone DQUOTE
p.xtake(`"`)
day := p.xdateDayFixed()
p.xtake("-")
month := p.xdateMonth()
p.xtake("-")
year := xint(p, p.xtaken(4))
p.xspace()
hours, minutes, seconds := p.xtime()
p.xspace()
name, zoneSeconds := p.xzone()
p.xtake(`"`)
loc := time.FixedZone(name, zoneSeconds)
return time.Date(year, month, day, hours, minutes, seconds, 0, loc)
}
// ../rfc/9051:6655 ../rfc/7888:330 ../rfc/3501:4801
func (p *parser) xliteralSize(maxSize int64, lit8 bool) (size int64, sync bool) {
// todo: enforce that we get non-binary when ~ isn't present?
if lit8 {
p.take("~")
}
p.xtake("{")
size = p.xnumber64()
if maxSize > 0 && size > maxSize {
// ../rfc/7888:249
line := fmt.Sprintf("* BYE [ALERT] Max literal size %d is larger than allowed %d in this context", size, maxSize)
err := errors.New("literal too big")
panic(syntaxError{line, "TOOBIG", err.Error(), err})
}
sync = !p.take("+")
p.xtake("}")
p.xempty()
return size, sync
}
var searchKeyWords = []string{
"ALL", "ANSWERED", "BCC",
"BEFORE", "BODY",
"CC", "DELETED", "FLAGGED",
"FROM", "KEYWORD",
"NEW", "OLD", "ON", "RECENT", "SEEN",
"SINCE", "SUBJECT",
"TEXT", "TO",
"UNANSWERED", "UNDELETED", "UNFLAGGED",
"UNKEYWORD", "UNSEEN",
"DRAFT", "HEADER",
"LARGER", "NOT",
"OR",
"SENTBEFORE", "SENTON",
"SENTSINCE", "SMALLER",
"UID", "UNDRAFT",
"MODSEQ", // CONDSTORE extension.
}
// ../rfc/9051:6923 ../rfc/3501:4957, MODSEQ ../rfc/7162:2492
// differences: rfc 9051 removes NEW, OLD, RECENT and makes SMALLER and LARGER number64 instead of number.
func (p *parser) xsearchKey() *searchKey {
if p.take("(") {
sk := p.xsearchKey()
l := []searchKey{*sk}
for !p.take(")") {
p.xspace()
l = append(l, *p.xsearchKey())
}
return &searchKey{searchKeys: l}
}
w, ok := p.takelist(searchKeyWords...)
if !ok {
seqs := p.xnumSet()
return &searchKey{seqSet: &seqs}
}
sk := &searchKey{op: w}
switch sk.op {
case "ALL":
case "ANSWERED":
case "BCC":
p.xspace()
sk.astring = p.xastring()
case "BEFORE":
p.xspace()
sk.date = p.xdate()
case "BODY":
p.xspace()
sk.astring = p.xastring()
case "CC":
p.xspace()
sk.astring = p.xastring()
case "DELETED":
case "FLAGGED":
case "FROM":
p.xspace()
sk.astring = p.xastring()
case "KEYWORD":
p.xspace()
sk.atom = p.xatom()
case "NEW":
case "OLD":
case "ON":
p.xspace()
sk.date = p.xdate()
case "RECENT":
case "SEEN":
case "SINCE":
p.xspace()
sk.date = p.xdate()
case "SUBJECT":
p.xspace()
sk.astring = p.xastring()
case "TEXT":
p.xspace()
sk.astring = p.xastring()
case "TO":
p.xspace()
sk.astring = p.xastring()
case "UNANSWERED":
case "UNDELETED":
case "UNFLAGGED":
case "UNKEYWORD":
p.xspace()
sk.atom = p.xatom()
case "UNSEEN":
case "DRAFT":
case "HEADER":
p.xspace()
sk.headerField = p.xastring()
p.xspace()
sk.astring = p.xastring()
case "LARGER":
p.xspace()
sk.number = p.xnumber64()
case "NOT":
p.xspace()
sk.searchKey = p.xsearchKey()
case "OR":
p.xspace()
sk.searchKey = p.xsearchKey()
p.xspace()
sk.searchKey2 = p.xsearchKey()
case "SENTBEFORE":
p.xspace()
sk.date = p.xdate()
case "SENTON":
p.xspace()
sk.date = p.xdate()
case "SENTSINCE":
p.xspace()
sk.date = p.xdate()
case "SMALLER":
p.xspace()
sk.number = p.xnumber64()
case "UID":
p.xspace()
sk.uidSet = p.xnumSet()
case "UNDRAFT":
case "MODSEQ":
// ../rfc/7162:1045 ../rfc/7162:2499
p.xspace()
if p.take(`"`) {
// We don't do anything with this field, so parse and ignore.
p.xtake(`/FLAGS/`)
if p.take(`\`) {
p.xtake(`\`) // ../rfc/7162:1072
}
p.xatom()
p.xtake(`"`)
p.xspace()
p.xtakelist("PRIV", "SHARED", "ALL")
p.xspace()
}
v := p.xnumber64()
sk.clientModseq = &v
// MODSEQ is a CONDSTORE-enabling parameter. ../rfc/7162:377
p.conn.enabled[capCondstore] = true
default:
p.xerrorf("missing case for op %q", sk.op)
}
return sk
}
// hasModseq returns whether there is a modseq filter anywhere in the searchkey.
func (sk searchKey) hasModseq() bool {
if sk.clientModseq != nil {
return true
}
for _, e := range sk.searchKeys {
if e.hasModseq() {
return true
}
}
if sk.searchKey != nil && sk.searchKey.hasModseq() {
return true
}
if sk.searchKey2 != nil && sk.searchKey2.hasModseq() {
return true
}
return false
}
// ../rfc/9051:6489 ../rfc/3501:4692
func (p *parser) xdateDay() int {
d := p.xdigit()
if s, ok := p.digit(); ok {
d += s
}
return xint(p, d)
}
// ../rfc/9051:6487 ../rfc/3501:4690
func (p *parser) xdate() time.Time {
dquote := p.take(`"`)
day := p.xdateDay()
p.xtake("-")
mon := p.xdateMonth()
p.xtake("-")
year := xint(p, p.xtaken(4))
if dquote {
p.take(`"`)
}
return time.Date(year, mon, day, 0, 0, 0, 0, time.UTC)
}